Wow the average person can walk a mile burning off just 10 grams of fat. With sufficient water, the average person can walk out their front door today and cover 500-1000 miles without needing to eat anything else........
That's just nuts !!
Fat is stored in the body in the form of triglyceride, which is comprised of three fatty acids attached to a molecule of glycerol. The fatty acids consist of chains of carbon atoms with hydrogen atoms attached. There is more stored energy (9 kcal) in a gram of fat than in an equal weight of carbohydrate (4 kcal/g). Typically, about 50,000 to 60,000 kcal of energy are stored as triglycerides in the entire mass of all of the adipocytes throughout the body. Obviously, there will be more energy stored in an obese person and less in an individual who has little body fat (Figure 1). Approximately 100 kcal of energy are expended per mile of walking, so most people have sufficient stores of triglyceride energy to walk 500-1,000 miles. Because this large amount of energy is stored in a relatively small mass of triglycerides, they provide a marvelous way for people to carry fuel as they move from place to place. In contrast, if all of this energy were stored as carbohydrate in glycogen, water molecules, which are very heavy, would be bound to the glycogen molecules, resulting in a total energy store weight of more than 100 pounds.